Chemical elements
    Physical Properties
    Chemical Properties
      Silver fluoride
      Silver subfluoride
      Silver chloride
      Silver subchloride
      Silver bromide
      Silver oxybromide
      Silver subbromide
      Silver iodide
      Silver hypochlorite
      Silver chlorite
      Silver chlorate
      Silver perchlorate
      Silver bromate
      Silver perbromate
      Silver iodate
      Silver periodates
      Silver suboxide
      Silver monoxide
      Higher oxides
      Silver subsulphide
      Silver sulphide
      Silver sulphite
      Silver sulphate
      Silver selenide
      Silver telluride
      Silver thiosulphate
      Silver dithionate
      Silver azide
      Silver hyponitrite
      Silver nitrite
      Silver nitrate
      Silver phosphides
      Silver hypophosphate
      Silver orthophosphate
      Silver pyrophosphate
      Silver metaphosphate
      Silver arsenite
      Silver arsenate
      Silver carbide
      Silver carbonate
      Silver cyanide
      Silver thiocyanate
      Silver borate
    PDB 1aoo-3kso

Silver cyanide, AgCN

A white, amorphous precipitate of the Silver cyanide, AgCN, is obtained by interaction of a silver salt and a cyanide in aqueous solution. It crystallizes from a hot concentrated solution of potassium carbonate in fine needles. It is unaffected by light, but heat eliminates one-half of the cyanogen, with production of silver "paracyanide." Both hydrochloric acid and mercuric chloride convert it into silver chloride. With hydrogen sulphide it yields Silver sulphide, and heating with sulphur transforms it into silver thiocyanate. Its heat of formation from silver and cyanogen is 3.6 Cal. There is some evidence of the existence of silver cyanide in two polymeric forms, AgCN and Ag2(CN)2. With hydrazine cyanide it forms colourless crystals, AgCN,N2H4, which blacken in contact with air.

Solution of silver or its cyanide in potassium cyanide forms potassium silver cyanide, KAg(CN)2, octahedral crystals stable in air, but blackened by light. As 20° C. its solubility is 25 grams per 100 grams of water.

Its heat of formation from the two cyanides is 5.6 Cal. Addition of silver chloride to its solution precipitates silver cyanide:

KAg(CN)2 + AgCl ⇔ 2AgCN + KCl.

A solution of the double cyanide is extensively employed as a bath for silver-plating.

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